Cyclin-dependent kinase, or CDK, is a type of enzyme protein that resides in eukaryotic cells and plays a key role in metabolism and cell turnover, a series of biological processes collectively referred to as the cell cycle. Several protein kinases are also classified as genes, accounting for about 2 percent of all human genes. The mechanism of cyclin-dependent kinase activity is based on phosphorylation, or the process of contributing phosphate groups to substrate proteins. However, for a protein to be modified by phosphorylation, it must form a complex with another type of protein known as a cyclin. This is why this particular specialized protein is called a cyclin-dependent kinase.
In addition to regulating cell function, the other significant activity associated with cyclin-dependent kinase is providing the pathway for signal transduction. In other words, cells can communicate with each other by enlisting cyclin-dependent kinase enzymes to serve as chemical messengers. While this process may be fascinating to biology enthusiasts, it is of primary interest to the medical community because of its involvement in disease development. In fact, impaired signal transduction is considered largely responsible for the initiation of many diseases, including heart disease, diabetes, cancer, and many autoimmune disorders.
One of the most promising applications with respect to the treatment of such diseases is the possibility of intercepting cyclin-dependent kinase activity in cells. In fact, some drugs designed to target and inhibit cyclin-dependent kinase have been shown to promote apoptosis, or cell death. This result is particularly significant in terms of combating tumor growth and cancer spread. Additionally, these drugs appear to affect neutrophil granulocytes, which contribute to the development of chronic inflammatory conditions such as arthritis. However, since these drugs can also affect the cyclin-dependent kinase-mediated pathway and cause unwanted side effects, more research is needed to ensure that they only target receptor cells.
There are also different types of cyclin-dependent protein kinases that can be targeted to help prevent a variety of reactions. For example, inhibiting cyclin-dependent kinase 2 may help deter the hair loss that often occurs while being treated with chemotherapy, while manipulating cyclin-dependent kinase 4 may affect the regulation of Rb, a protein linked to hair loss. tumor.
Protein kinases also function differently towards cellular regulation. While each type initiates phosphorylation by borrowing a phosphate group from adenosine-5-triphosphate (ATP), it must also be able to attach phosphates to an available hydroxyl group belonging to one of the three amino acids. Most kinases accomplish this by targeting the amino acids serine and threonine, while others seek out tyrosine. However, there are some that are compatible with all three.